Secretary of State Hillary Clinton teared up Wednesday talking about the deaths of Ambassador J. Chris Stevens and three other Americans killed in an attack on the U.S. consulate in Benghazi, Libya, on Sept. 11. “For me, this is not just a matter of policy. It’s personal. I stood next to President Obama as the Marines carried those flag-draped caskets off the plane at Andrews,” Clinton said. “I put my arms around the mothers and fathers, the sisters and brothers, the sons and daughters, and the wives left alone to raise their children.”

Clinton was testifying before the Senate Foreign Relations Committee, her first, and likely only, testimony before Congress on the attack. Later on Wednesday, she is scheduled to appear before the House Foreign Relations Committee. Senator John Kerry is expected to be confirmed as Clinton’s successor at State by early next week. Clinton had been scheduled to testify last month before a series of health problems landed her in the hospital, forcing a postponement.

Clinton again took full responsibility for what happened and said her department is in process of implementing all 19 of the recommendations by an independent panel that investigated the attack. She noted that she appointed the first-ever Deputy Secretary of State responsible for high-risk posts and implemented an annual review led by the Secretary of all these posts.

At times Clinton grew angry at Republicans’ focus on U.N. Ambassador Susan Rice’s comments the Sunday after the attacks that the situation had been nothing more than a protest gone haywire. It was later found that the assault on the consulate was a coordinated terrorist attack, not a flash protest. “I just want to say that, you know, people have accused Ambassador Rice and the Administration of, you know, misleading Americans. I can say, trying to be in the middle of this and understanding what was going on, nothing could be further from the truth. Was information developing? Was the situation fluid? Would we reach conclusions later that weren’t reached initially?” a clearly exasperated Clinton said, her voice rising, chopping her left hand on the table before her with each question. “What difference at this point does it make?”

Clinton also was careful to underline that Benghazi, while a tragedy, should not become an excuse for the U.S. to become more isolationist. “This is a great opportunity as well as a serious threat to our country. I hope we seize the opportunity. It’s not going to be easy, because these new countries have no experience with democracy. They don’t have any real experience among the leaders in running countries, in doing security,” Clinton said. “[W]e have to recognize this is a global movement. We can kill leaders, but until we help establish strong democratic institutions, until we do a better job communicating our values and building relationships, we’re going to be faced with this level of instability.”